Probably the easiest way to catch a Pikachu is not even catch it at all. If you haven't started playing Pokemon GO yet, you'll be able to pull this one off. You can actually start with Pikachu if you just wait and walk away. Don't pick the first three starters that the infamous Professor Willow initially gives you (Squirtle, Bulbasaur, and Charmander). If you have a tad bit of patience, you can grab Pikachu after a bit as your starter Pokemon.

However, if you didn't grab Pikachu with that trick, you'll have to catch one yourself either by hatching Pikachu from a 2 km Lucky Egg, or by finding it yourself.

Since Pikachu is an electric Pokemon you're going to have to find him in industrial areas where there's a lot of power. This can include areas near power plants, schools and college campuses, business parks, science museums, industrial districts, and other places of industry.

The fastest way to find a Pikachu is to use one of the various Pokemon GO map apps. These will show you where so-called 'nests' of Pokemon and give you an overview of where the closest Pikachu is so you can go find it!